This disclosure relates to electrochemical cell systems, and in particular to gas/liquid phase separators for electrolysis cell systems.
Electrochemical cells are energy conversion devices, usually classified as either electrolysis cells or fuel cells. Proton exchange membrane electrolysis cells can function as hydrogen generators by electrolytically decomposing water to produce hydrogen and oxygen gases. Referring to FIG. 1, a section of an anode feed electrolysis cell of the prior art is shown generally at 10 and is hereinafter referred to as xe2x80x9ccell 10.xe2x80x9d Reactant water 12 is fed into cell 10 at an oxygen electrode (anode) 14 to form oxygen gas 16, electrons, and hydrogen ions (protons) 15. The chemical reaction is facilitated by the positive terminal of a power source 18 connected to anode 14 and the negative terminal of power source 18 connected to a hydrogen electrode (cathode) 20. Oxygen gas 16 and a first portion 22 of the water are discharged from cell 10, while protons 15 and a second portion 24 of the water migrate across a proton exchange membrane 26 to cathode 20. At cathode 20, hydrogen gas 28 is removed, generally through a gas delivery line. The removed hydrogen gas 28 is usable in a myriad of different applications. Second portion 24 of water is also removed from cathode 20.
An electrolysis cell system may include a number of individual cells arranged in a stack with reactant water 12 being directed through the cells via input and output conduits formed within the stack structure. The cells within the stack are sequentially arranged, and each one includes a membrane electrode assembly defined by a proton exchange membrane disposed between a cathode and an anode. The cathode, anode, or both may be gas diffusion electrodes that facilitate gas diffusion to the proton exchange membrane. Each membrane electrode assembly is in fluid communication with flow fields adjacent to the membrane electrode assembly, defined by structures configured to facilitate fluid movement and membrane hydration within each individual cell.
The second portion 24 of water discharged from the cathode side of cell 10, which is entrained with hydrogen gas, is fed to a phase separation unit to separate the hydrogen gas from the water, thereby increasing the hydrogen gas yield and the overall efficiency of cell 10 in general. Phase separation units utilized in current hydrogen generation and fuel cell systems employ trap designs within pressure vessels. High-pressure trap designs incorporate pivoting float offsets to accomplish proper lift by using a lever and fulcrum configuration. In order to be properly operational, such systems generally require excessive space within the system enclosures.
A gas/liquid phase separator for an electrolysis cell is disclosed. The gas/liquid separator includes a vessel and a float in operable communication with each other. The vessel includes a fluid inlet and first and second fluid outlets. A fluid stream comprising gas and liquid is received in the vessel through the fluid inlet, and at least a portion of the gas exits the vessel through the second fluid outlet. The float is configured to interface with the first fluid outlet and to either maintain or prevent fluid communication across the first fluid outlet when the float is in at least partial contact with the first fluid outlet.